Parents are increasingly seeking alternative forms of education such as home schooling or Steiner schools to free their children from the state sector's regime of testing and targets, academics suggest today. Most English pupils now start formal learning at four years old, among the youngest in the world, and go on to be the most tested throughout their education, according to a series of in-depth reports which will feed into a major review of primary schooling by Cambridge University.

Many parents are now considering alternative forms of education and more are opting to home-educate their children. The government should learn from the way children are taught in alternative settings such as Steiner schools where they learn through play, the academics say.

"Both the numbers opting for home schooling and the range of motivations of those wishing to do so have expanded considerably in recent years. One substantial and growing group is comprised of those who have abandoned formal schooling because they believe it to be too constrained," according to a paper by James Conroy and colleagues at Glasgow University. An estimated 50,000 children are being educated at home. A second paper, also released today, reveals that English children are attending school earlier, and spend more days a year at school, and in increasingly large institutions.

Most children now start school at four, the second study, The Structure of Primary Education, by the National Foundation for Educational Research, finds, despite the legal age being after their fifth birthday. One factor has been rising demand for childcare as more women work full-time.

The school starting age has not changed since it was introduced in 1870 to prevent child labour abuses. The average school size in England in 2006 was 224 pupils, compared with 128 in Scotland and higher than any other country in the study. A third study, on the curriculum and assessment, led by Kathy Hall at the National University of Ireland in Cork, says that English schoolchildren are among the most tested in the world. "No other country appears to be so preoccupied with national standards," it says. The research says home-educated children perform better and that children from disadvantaged backgrounds can improve disproportionately. Home-educated pupils are less likely to watch TV or spend hours on computers.

The Cambridge review, led by Professor Robin Alexander, is the biggest independent review of primary schooling in 40 years.